Conventional instruments and methods for obtaining access to regions within the body by dissecting tissue and retracting tissue and organs have been previously accomplished through various mechanical methods. Previous devices have included expandable tissue dissectors and retractors used for dissecting or moving sub-surface tissue in arthroscopic and endoscopic surgery percutaneously introduced into a patient through small incisions made in the skin.
Many of these devices are configured to simply expand from a low profile into an expanded profile to simply provide a surface, whether by an expanded structure or via a sheath or covering, for retracting tissue regions within the body. Other devices are also expandable into an expanded profile to not only provide a retraction surface but also to dissect sub-surface regions of tissue. In either case, these devices are typically configured to mechanically expand in a number of different planes while other devices are configured to expand within a single plane. Most of these tools are mechanically expandable in a number of different configurations, for example, expandable mechanical trusses, pivoting interleaved configurations, projecting loops, etc.
Still other devices have utilized expandable balloons which are inflated within the patient through various methods. Generally, expansion is accomplished by inflating the balloon with a fluid or a gas, e.g., carbon dioxide, water, saline, etc., until the balloon is sufficiently expanded. Such balloons have also been utilized for retraction of organs and tissue regions once expanded. However, such balloons are typically lacking because they generally lack sufficient rigidity and cannot be controlled to conform to various sizes or shapes for precise application. Moreover, adequate retraction of tissue can only be accomplished when the balloon is fully expanded.
Accordingly, there is a need for instruments which are sufficiently minimally invasive for passage into a patient and which are also sufficiently rigid and precisely controllable.